430 Duplicate Twins and Double Monsters 



be complete without including the many twins and triplets themselves^ 

 who have in all cases submitted to the ordeal of being printed with 

 exemplary patience, and who in some cases (Nos. XI and XV) have 

 taken the prints themselves. 



EXPLANATION OF DESCRIPTIVE FORMULA. 



The method of formulating the arrangement of the friction ridges 

 of the palm, as given in my previous articles on the subject, and espe- 

 cially in the last one (Popular Sci. Monthly, Sept., 1903), makes it 

 possible to easily describe and compare the large amount of material in 

 the collection listed above. In preparing this description my object has 

 been to formulate each palm without prejudice, losing sight, so far as 

 possible, of the degree of similarity between the individuals of each set. 



x^Lfter going through them in this way, however, I have compared them 

 with the previous decisions as to identity, and am willing to confess 

 that I have occasionally added an explanation in those cases in which 

 the formulae fail to suggest the close similarity that is actually present, 

 marking such additions in all cases by placing them between brackets. 

 That this is occasionally necessary may be acknowledged by imagining 

 the not infrequent case of two main lines which pass in opposite direc- 

 tions very near one another, and where the variation of a single ridge 

 may cause either of the two to be the upper line, or may cause them to 

 meet and fuse. If we imagine, for example, lines C and D in such 

 mutual relations as these, the results expressed in formulae would give 

 for the first two figures either 7.5 (with line D above), 9.7 (with line C 

 above), or, finally, 8.6 (with a fusion of the two lines in question), a 

 difference of formulation which is very misleading when we consider 

 that these three conditions may be almost exact equivalents of one 

 another. 



The formulations here given, aided by an occasional explanation in 

 brackets, will furnish a brief but concise and definite description of all 

 the palms listed above; and a comparison of this with the classification 

 based upon the facial resemblance and general appearance will easily 

 show whether the correspondence between the two, as demanded by the- 

 ory, be warranted or not. As explained in the article referred to, each 

 formula consists of four numbers, which designate the termini, and 

 hence the mutual relationships, of the four main lines (the " primary " 

 lines of the 1902 articles) in the reverse order, beginning with line D. 

 The significance of the various numbers is shown by the diagram (Fig. 6) 

 reprinted from the Popular Science Monthly with the kind permission 



